Hillary Clinton dropped another presidential primary to Bernie Sanders, who put West Virginia in his column on Tuesday and demonstrated again the appeal of his populist message in states struggling economically.

The Vermont senator led in the polls heading into the balloting and pulled away by 15 percentage points in a state that illustrated central themes of the 2016 campaign attracting millions of voters feeling left behind or poorly served by government.

His win, however, did not brighten prospects for Sanders overtaking Clinton at this stage of the race. He gained only a few more delegates than she, and he admitted that his path to the nomination remains very narrow.

Yet, his victories energize his huge and enthusiastic pool of supporters, generate headlines and sustain his long-shot mathematical chances. Moreover, the more he demonstrates political potency, the more he strengthens his ability to influence the direction of the general election campaign and his future role in Democratic politics.

He is also forcing Clinton to stay in the grinding primary fight longer instead of solely focusing on Donald Trump and the general election.

Trump, running unopposed on the Republican side, also won West Virginia and added Nebraska to his win column, solidifying his support a week after becoming the presumptive GOP presidential nominee .

Trump, the brash celebrity business titan from New York City who has unsettled the GOP in Washington, and Sanders the socialist from a rural state who has run a surprisingly resilient campaign, leveraged their shared defiance of establishment politics and strident anti-trade rhetoric in capturing the Mountain State, where the once mighty coal and steel industries have diminished and jobs are harder to come by.

Speaking to a throng of cheering supporters in Salem, Ore., on Tuesday night, Sanders reported what he called a “tremendous” win in West Virginia.

"West Virginia is a working class state. And like many other states in this country, including Oregon, working people are hurting. What the people of West Virginia said today and what the people of Oregon and Kentucky will say next week is we need an economy that works for all of us, not just the one percent.”

Clinton was met in West Virginia last week by throngs of protesters , angry about her calls to replace coal with renewable energy. Her comments at a CNN town hall in March that "We're gonna put a lot of coal miners and coal companies out of business" angered voters in coal country.

Sanders, who has also said the country needs to move away from its reliance on fossil fuels, has pledged to keep jobs in coal mining communities.

Clinton's setback showed particularly that she has a lot of work to do in the manufacturing centers of the Rust Belt as well as in states like West Virginia and Kentucky. Sanders has effectively blunted her momentum in those regions with his populist economic message resonating especially with independents.

Trump has done well in those states, too, driving home nationalistic themes that especially attract working-class whites negatively impacted by the nation's slow recovery from the Great Recession.

[Hillary Clinton Feels the Heat in Coal Country] Sanders acknowledged Tuesday night that he has an uphill climb to the nomination but vowed to stay in the race to the end. "We are in this campaign to win the Democratic nomination,” he said, before adding that whoever wins "must defeat Donald Trump.”

Sanders netted five more delegates than Clinton with the victory in West Virginia and raised his total of pledged delegates and superdelegates to 1,469, according to the AP. Clinton has 2,239 total delegates and needs just 144 to put the matter to rest.

Trump wasn’t tested in the Mountain or Cornhusker states with both of his remaining primary rivals dropping out after his decisive victory in Indiana last week put to rest any questions of a contested convention.

Trump added 39 delegates to his total with the West Virginia and Nebraska wins, bringing him to within 129 delegates of the 1,237 needed to secure the nomination in Cleveland this July, according to AP figures.

[Trump to Meet with GOP Leaders] Although out of the race, Ted Cruz and Ohio Gov. John Kasich remained on the West Virginia and Nebraska ballots, and Republican primary voters demonstrated again that they strongly back Trump while GOP leaders in Washington and other party stalwarts wrestle with his candidacy and debate supporting him or not.